Writing transparent text in jpeg

Question

Everywhere it is said about adding text on a transparent image. I would like to add text as a watermark (the so-called transparent text) to the classic jpeg image. I tried everything that I found. Does anyone have a solution? Could be solvable at all?

I would like to use GD (not imagick) because the project is built on GD.

thanks

Edit: This is what I use

$textBox = imagettfbbox($fontSize, $angle, $font, $text); //file is orig image $im = imagecreatefromjpeg($file); $transparent = imagecolorallocate($im, 250, 250, 250); //does not help - text disapper //$transparent = imagecolorallocatealpha($im, 0, 0, 0, 127); //does not help, burn whole to image //imagealphablending($im, false); //imagesavealpha($im, true); //calculate position - $imageInfo is getsizeimage on orig image $textX = ($imageInfo[0] / 2) - ($textBox[2] / 2); $textY = ($imageInfo[1] / 2) - ($textBox[5] / 2); //does not help //imagecolortransparent ($im, $transparent); imagettftext($im, $fontSize, $angle, $textX, $textY, $transparent, $font, $text); header("Content-Type: image/jpeg"); imagejpeg($im); 

A simple solution

 Color is neccessary set by imagecolorresolvealpha($im, 0, 0, 0, 100); 

Answer 1

Try it, it will work for me ...
Php script add text as watermark

Here is the link where I got it from

 <?php //---------------------------------------------------------------- // render_text_on_gd_image // THE FUNCTION THAT ACTUALLY RENDERS THE STRING //---------------------------------------------------------------- define( 'WATERMARK_MARGIN_ADJUST', 5 ); define( 'WATERMARK_FONT_REALPATH', 'c:\\windows\\fonts\\' ); function render_text_on_gd_image( &$source_gd_image, $text, $font, $size, $color, $opacity, $rotation, $align ) { $source_width = imagesx( $source_gd_image ); $source_height = imagesy( $source_gd_image ); $bb = imagettfbbox_fixed( $size, $rotation, $font, $text ); $x0 = min( $bb[ 0 ], $bb[ 2 ], $bb[ 4 ], $bb[ 6 ] ) - WATERMARK_MARGIN_ADJUST; $x1 = max( $bb[ 0 ], $bb[ 2 ], $bb[ 4 ], $bb[ 6 ] ) + WATERMARK_MARGIN_ADJUST; $y0 = min( $bb[ 1 ], $bb[ 3 ], $bb[ 5 ], $bb[ 7 ] ) - WATERMARK_MARGIN_ADJUST; $y1 = max( $bb[ 1 ], $bb[ 3 ], $bb[ 5 ], $bb[ 7 ] ) + WATERMARK_MARGIN_ADJUST; $bb_width = abs( $x1 - $x0 ); $bb_height = abs( $y1 - $y0 ); switch ( $align ) { case 11: $bpy = -$y0; $bpx = -$x0; break; case 12: $bpy = -$y0; $bpx = $source_width / 2 - $bb_width / 2 - $x0; break; case 13: $bpy = -$y0; $bpx = $source_width - $x1; break; case 21: $bpy = $source_height / 2 - $bb_height / 2 - $y0; $bpx = -$x0; break; case 22: $bpy = $source_height / 2 - $bb_height / 2 - $y0; $bpx = $source_width / 2 - $bb_width / 2 - $x0; break; case 23: $bpy = $source_height / 2 - $bb_height / 2 - $y0; $bpx = $source_width - $x1; break; case 31: $bpy = $source_height - $y1; $bpx = -$x0; break; case 32: $bpy = $source_height - $y1; $bpx = $source_width / 2 - $bb_width / 2 - $x0; break; case 33; $bpy = $source_height - $y1; $bpx = $source_width - $x1; break; } $alpha_color = imagecolorallocatealpha( $source_gd_image, hexdec( substr( $color, 0, 2 ) ), hexdec( substr( $color, 2, 2 ) ), hexdec( substr( $color, 4, 2 ) ), 127 * ( 100 - $opacity ) / 100 ); return imagettftext( $source_gd_image, $size, $rotation, $bpx, $bpy, $alpha_color, WATERMARK_FONT_REALPATH . $font, $text ); } //---------------------------------------------------------------- // imagettfbbox_fixed // FIX FOR THE BUGGY IMAGETTFBBOX IMPLEMENTATION IN GD LIBRARY //---------------------------------------------------------------- function imagettfbbox_fixed( $size, $rotation, $font, $text ) { $bb = imagettfbbox( $size, 0, WATERMARK_FONT_REALPATH . $font, $text ); $aa = deg2rad( $rotation ); $cc = cos( $aa ); $ss = sin( $aa ); $rr = array( ); for( $i = 0; $i < 7; $i += 2 ) { $rr[ $i + 0 ] = round( $bb[ $i + 0 ] * $cc + $bb[ $i + 1 ] * $ss ); $rr[ $i + 1 ] = round( $bb[ $i + 1 ] * $cc - $bb[ $i + 0 ] * $ss ); } return $rr; } //---------------------------------------------------------------- // CREATE WATERMARK FUNCTION //---------------------------------------------------------------- define( 'WATERMARK_OUTPUT_QUALITY', 90 ); function create_watermark_from_string( $source_file_path, $output_file_path, $text, $font, $size, $color, $opacity, $rotation, $align ) { list( $source_width, $source_height, $source_type ) = getimagesize( $source_file_path ); if ( $source_type === NULL ) { return false; } switch ( $source_type ) { case IMAGETYPE_GIF: $source_gd_image = imagecreatefromgif( $source_file_path ); break; case IMAGETYPE_JPEG: $source_gd_image = imagecreatefromjpeg( $source_file_path ); break; case IMAGETYPE_PNG: $source_gd_image = imagecreatefrompng( $source_file_path ); break; default: return false; } render_text_on_gd_image( $source_gd_image, $text, $font, $size, $color, $opacity, $rotation, $align ); imagejpeg( $source_gd_image, $output_file_path, WATERMARK_OUTPUT_QUALITY ); imagedestroy( $source_gd_image ); } //---------------------------------------------------------------- // FILE PROCESSING FUNCTION //---------------------------------------------------------------- define( 'UPLOADED_IMAGE_DESTINATION', 'originals/' ); define( 'PROCESSED_IMAGE_DESTINATION', 'images/' ); function process_image_upload( $Field ) { $temp_file_path = $_FILES[ $Field ][ 'tmp_name' ]; $temp_file_name = $_FILES[ $Field ][ 'name' ]; list( , , $temp_type ) = getimagesize( $temp_file_path ); if ( $temp_type === NULL ) { return false; } switch ( $temp_type ) { case IMAGETYPE_GIF: break; case IMAGETYPE_JPEG: break; case IMAGETYPE_PNG: break; default: return false; } $uploaded_file_path = UPLOADED_IMAGE_DESTINATION . $temp_file_name; $processed_file_path = PROCESSED_IMAGE_DESTINATION . preg_replace( '/\\.[^\\.]+$/', '.jpg', $temp_file_name ); move_uploaded_file( $temp_file_path, $uploaded_file_path ); //---------------------------------------------------------------- // PARAMETER DESCRIPTION // (1) SOURCE FILE PATH // (2) OUTPUT FILE PATH // (3) THE TEXT TO RENDER // (4) FONT NAME -- MUST BE A *FILE* NAME // (5) FONT SIZE IN POINTS // (6) FONT COLOR AS A HEX STRING // (7) OPACITY -- 0 TO 100 // (8) TEXT ANGLE -- 0 TO 360 // (9) TEXT ALIGNMENT CODE -- POSSIBLE VALUES ARE 11, 12, 13, 21, 22, 23, 31, 32, 33 //---------------------------------------------------------------- $result = create_watermark_from_string( $uploaded_file_path, $processed_file_path, 'Copyrights (c) 2008', 'arial.ttf', 14, 'CCCCCC', 75, 0, 32 ); if ( $result === false ) { return false; } else { return array( $uploaded_file_path, $processed_file_path ); } } //---------------------------------------------------------------- // END OF FUNCTIONS //---------------------------------------------------------------- $result = process_image_upload( 'File1' ); if ( $result === false ) { echo '<br>An error occurred during file processing.'; } else { echo '<br>Original image saved as <a href="' . $result[ 0 ] . '" target="_blank">' . $result[ 0 ] . '</a>'; echo '<br>Watermarked image saved as <a href="' . $result[ 1 ] . '" target="_blank">' . $result[ 1 ] . '</a>'; } ?> 

Php script to add image as watermark

 <?php header('content-type: image/jpeg'); $watermark = imagecreatefrompng('watermark.png'); $watermark_width = imagesx($watermark); $watermark_height = imagesy($watermark); $image = imagecreatetruecolor($watermark_width, $watermark_height); $image = imagecreatefromjpeg($_GET['src']); $size = getimagesize($_GET['src']); $dest_x = $size[0] - $watermark_width - 5; $dest_y = $size[1] - $watermark_height - 5; imagecopymerge($image, $watermark, $dest_x, $dest_y, 0, 0, $watermark_width, $watermark_height, 100); imagejpeg($image); imagedestroy($image); imagedestroy($watermark);